Field of the Invention
The present invention relates to an interference check system for interference between a machine tool and a robot.
Description of the Related Art
Robots are widely used in combination with machine tools for workpiece attachment and removal or the like. Since a robot can get into a machine tool to attach or remove a workpiece, it is desirable that the machine tool and the robot be checked for interference.
Techniques described in Japanese Patent Applications Laid-Open Nos. 2008-27376 and 2010-244256 are used for interference check for a machine tool. According to these techniques, a numerical controller for controlling the machine tool outputs a preceding position, and the interference check is performed based on the output information so that the machine tool can be stopped before interference.
In checking interference between robots, moreover, teaching programs for the robots are read in advance by a technique described in Japanese Patent Application Laid-Open No. 2006-68857.
In order to check the interference between the machine tool and the robot by these conventional techniques, however, it is necessary to use the techniques described in Japanese Patent Applications Laid-Open Nos. 2008-27376 and 2010-244256 in which the preceding position is output by the numerical controller for controlling the machine tool. Also, it is necessary to output a preceding position on the robot side so that the interference check can be performed based on the preceding positions output individually from the numerical controller and a robot controller.
If an attempt is made to apply the technique of Japanese Patent Application Laid-Open No. 2006-68857 for robot-robot interference check to interference check between a machine tool and a robot (i.e., if this technique is applied regarding the machine tool as one robot), the robot can certainly obtain an NC program as information equivalent to a teaching program from a numerical controller for controlling the machine tool. Since a lead time for calculating a preceding position on the numerical controller dynamically varies depending on the type of interpolation, look-ahead state in a look-ahead buffer, or command for suppressing look-ahead, however, the NC program for controlling the machine tool cannot easily calculate the preceding position of the robot according to the lead time of the machine tool. Due to this problem, interference between the machine tool and the robot cannot be checked.
In contrast, even if the robot teaching program is obtained on the side of the numerical controller for controlling the machine tool, the lead time for calculating the preceding position also dynamically varies depending on the type of interpolation, look-ahead state in the look-ahead buffer, or command for suppressing look-ahead, so that it is difficult to calculate the preceding position of the machine tool according to the lead time of the robot.